Propellant and rocket propulsion method



United States atent 3,117,415 PRQPELLANI AND ROCKET PROPULSIGN R IETHQD Stanley A. Greene, Woodland Hills, Calif, assignor to North American Aviation, inc. No Drawing. Filed Apr. 2, 1959, Ser. No. 394,063 26 Claims. (Cl. so-35.4

This invention relates to a novel rocket propellant. More particularly, this invention relates to a novel and improved rocket propellant, and a method of providing rocket propulsion.

The criterion by which rocket propellants are classified is specific impulse, I defined as thrust, in pounds, divided by the total mass flow of fuel and oxidizer, in pounds, per second. Specific impulse is thus given in units of seconds. Oxidizer-fuel propulsion system compositions with a high specific impulse are Well known in the art. Such systems, however, usually employ a nonstorable oxidizer, such as liquid oxygen for example. The non-storability of certain rocket propellant components results in a tactical disadvantage in providing rockets which cannot be held in a full state of instantaneous readiness. Consequently, a search has centered on the development of a high energy, storaole, liquid system which is invariably hypergolic (spontaneously combustible on fuel-oxidizer contact) and remains so even at very low pressures (high altitudes) and temperatures. Chlorine trifiuoride, CF is a storable oxidizer. Hydrazine is a well known rocket fuel. In order to derive the greatest possible benefit from using an oxidizer with an extremely wide liquid range, as chlorine trifluoride, the fuel itself should have a correspondingly large liquid range. in this case, hydrazine must be eliminated due to its high freezing point. Therefore, a need exists for a fuel having a low freezing point and a high specific impulse when used with the storable oxidizer.

It is an object of this invention to provide a new oxidizerfuel system. Anoter object of this invention is to pro vide a storable rocket fuel system or composition possessing a high specific impulse. It is also an object of this invention to provide a storable rocket fuel system. A further object is to provide a rocket fuel composition having a low freezing point. Another object is to provide a method of producing thrust. The above and other objects of this invention will become apparent from the discussion which follows.

The objects of this invention are accomplished by the use of substituted-hydroxylamines, hereinafter referred to simply as hydroxylamines, as rocket fuels. Hence, an embodiment of this invention comprises a method of producing thrust comprising ejecting from a reaction chamber the gaseous products produced by the spontaneous combustion of an oxidizer and a substituted-hydroxylamine fuel having a general formula wherein each of R R and R is selected from the class consisting of hydrogen and hydrocarbon groups having from 1 to about 12 carbon atoms and wherein at least one of said R R and R groups is a hydrocarbon group.

When the hydroxylamine has a single hydrocarbon substituent on the oxygen atom, it is called an whydroxylamine, or O-hydroxylamine. When, on the other hand, the hydroxylamine has a single hydrocarbon group on the nitrogen atom, it is called a ,B-hydroxylamine, or N- hydroxylamine.

The hydrocarbon groups on the hydroxylamine can be alkyl, cycloalkyl, aryl, arylkyl, alkaryl, etc. Non-limitidliAlS "ice ing examples of the hydroxylamines are: alpha methylhydroxylamine, H NOCH beta methylhydroxylamine, CI'IgNHOIL alpha ethylhydroxylamine, beta ethylhydroxylaminc, alpha octylhydroxylamine, beta dodecylhydroxylamine, otfi dimethylhydroxylamine, ot,fi,/i trimethylhydroxylamine, (CH NOCH 01,5,5 tripropylhydroxylamine, ot-benzylhydroxylamine, ,B-ethylhydroxylamine, B-phenylhydroxylamine, O tolylhydroxylamine, etc. l-lydroxylamines having from 1 to about 9 carbon atoms are preferred since their use provides greater thrust and therefore higher specific impulse. Hydroxylamines providing better performance are those having but one carbon in the hydrocarbon substituent, namely, methylsubstituted hydroxylamines. Especially preferred are the monomethylhydroxylamines, since the use of such compounds results in optimum specific impulse. Of the monomethylhydroxylamines, the O-methylhydroxylamine serves best as a liquid propellant because of its low freezing point of about 86 C.

An example of a propellant fuel system of this invention is the use in a rocket motor of O-methylhydroxylamine as the fuel and chlorinetrifiuoride as the oxidizer, with an oxidizer-to-fuel ratio equivalent to 0.9 of the stoichiometric ratio either in terms of weight percent or molecule percent.

Because of the low melting point of the hydroxylamines, they may be used in rocket fuel mixtures together with other fuels, such as hydrazine. Hydroxylamines and hydraz ne are mixed together to provide a rocket fuel having a lower freezing point than hydrazine by itself. Such mixed fuels benefit from the high specific impulse which is a characteristic of hydrazine. There is no substantial loss in specific impulse due to presence in the hydrazine of methylhydroxylamine because the specific impulse of the latter is almost as high as that of hydrazine. Hydroxylamines are also used in mixtures with unsymmetrical diamethyl hydrazine. UDMH, although O-methylhydroxylamine is superior fuel since it has a density impulse which is 4.5 percent greater than that of UDMH. in general, substituted-hydroxylamines can be used with hydrazine and substituted-hydrazines. Hence, an embodiment of this invention is a rocket fuel composition of matter comprising hydroxylamines having the general formula wherein R R and R are selected from the class consisting of hydrogen and hydrocarbon groups having from 1 to about 12 carbon atoms, together with at least 0.1 wt. percent, based on the total weight of the composition, of hydrazine compounds having the general formula R R NNR R wherein each of R R R and R is selected from the class consisting of hydrogen and hydrocarbon groups having from 1 to about 12 carbon atoms and wherein at least about of the sum of said R R R and R groups are hydrogen atoms, wherein the amount of total hydrazine compounds is from about 0.1 wt. percent to about 99.9 wt. percent, based on the total weight of the hydroxylamines and hydrazines present.

Preferably, the hydrazines which are mixed with the hydroxylamines are such that at least 50% of the sum of the R R R and R groups are hydrogen atoms. It is found that in this case a fuel mixture is obtained which has the greatest specific impulse possible with the added advantage of providing a factor of stability to the composition against shock detonation or thermal decomposition. An example of a hydroxylamine-hydrazine propellant fuel composition is one containing 1 wt. percent O-methylhydroxylamine and about 99 wt. percent hydrazine, based on the total weight of the two comoponents. Another example is a composition containing about 99 wt. percent O-methylhydroxylamine and about 1 wt. percent hydrazine.

The amount of hydrazines in the composition can vary from about 0.1 wt. percent to about 99.9 wt. percent, based on the total weight of the hydroxylamine-hydrazine present. Hydrazines present in a hydroxylamine composition act to desensitize the latter with regard to shock detonation. While 0.1 wt. percent hydrazines is used for this purpose, 0.5 wt. percent is a more practical amount to use in order to achieve a significant effect and the use of the latter amount constitutes an embodiment of this invention. A preferred embodiment constitutes the use of at least about 1 wt. percent hydrazines for a more significant desensitization. Hydroxylamines lower the freezing point of hydrazine and improve the ignition characteristics at low temperatures considerably without detracting from the effectiveness of hydrazine as a propellant. Substituted-hydroxylamines in the amount of about 0.1 Wt. percent, based on the weight of the hydroxylamines and hydrazines, are effective inthis respect. It is, however, preferred to use at least about 0.5 wt. percent hydroxylamines in order to achieve a significant improvement. Especially preferred is the use of at least about 1 Wt. percent of the hydroxylamines, when considerable improvement in the low temperature characteristics of the fuel are observed. Hence, the amounts of hydrazines in hydroxylamine-hydrazine compositions range from about 0.1 wt. percent to about 99.9 wt. percent, with a preferred range of from about 0.5 wt. percent to about 99.5 wt. percent, and an especially preferred range of from about 1 wt. percent to about 99 wt. percent. Amounts of hydrazine of from about 5 wt. percent to about 95 wt. percent are preferred in order to take a greater advantage of the enhancement of the good properties of one component by the presence of the other.

Thehydroxylamine fuels of this invention may also be used in conjunction with certain other additives employed for the purpose of stabilizing the fuel against thermal decomposition. The additives may be amino nitrogen-containing hydrocarbons such as ethylenediamine, hydroxy-substituted' hydrocarbons such as ethanol, hydroxy and amino nitrogen-containing hydrocarbons such as ethanolamine, ketones such as acetone and urea, etc. The fuel composition may contain one or more of the above mentioned additives.

An embodiment of this invention is,.therefore, acomposition of matter comprising (1) hydroxylamines having the general formula whereinR R and R are selected from the class consisting of hydrogen and hydrocarbon groups having-from l to about 12 carbon atoms, together with (2) at least 0.1 wt. percent, based on the weight of said hydroxylamines, of at least one compound selected from the class consisting of (a) hydrazine componds havingthe general formula R R NNR R wherein each of R R R and R is selected from the class consisting of hydrogen and hydrocarbon groups having from 1 to about 12 carbon atoms and wherein at least about 75% of the sum of said R R R and R groups are hydrogen atoms, (b) carbon, hydrogen, and nitrogen-containing compounds having from 1 to about'12 carbon atoms and from 1 to about 7 nitrogen atoms, (c) carbon,'hydrogen, and oxygen-containing compounds having from 1 to about 12 carbon atoms, from 1 to about 6 hydroxy groups, and from to about ether-linked oxygen atoms therein, (d) carbon, hydrogen, oxygen, and nitrogen-containing compounds having from 2 to about 12 carbon atoms, from 1 to about 3 nitrogen atoms, from 1 to about 3 hydroxy groups, and from 0 to about 3 ether-linked oxygen atoms, (0) carbon, hydrogen, and oxygen-containing compounds having from 1 to about 12 carbon atoms, from 1 to about 3 C:O

groups, and 0 to about 2 amino nitrogen atoms; wherein the amount of total hydrazine compounds is not more than about 99.9 wt. percent, based on the total weight of the hydroxylamines and hydrazines present, and wherein the amount of combined said hydroxylamines and hydrazines is at least about 25 wt. percent, based on the total weight of saidcomposition.

The hydrazine-type compound employed in the composition of this invention has the general formula R R NNR R wherein R R R and R are hydrogens or hydrocarbon groups. When hydrocarbon groups are substituted for the hydrogens on hydrazine, the specific impulse of the compound is decreased, speaking in terms of rocket fuel performance. Hence, an embodiment of this invention comprises a composition in which at least about 75% of the total number of R R R and R groups in the composition as a whole are hydrogen atoms. A preferred embodiment comprises a composition in which at least about of the total number of the R R R and R groups in the hydrazine compounds as a whole are hydrogen atoms in which case a minimum decrease in specific impulse is brought about. Another embodiment is a composition in which the hydrazine-type compound has at least one hydrogen atom attached to each nitrogen, as when R and R are hydrogen atoms. In the latter instance, the performance and physical properties of the hydrazine compound as a liquid rocket fuel are enhanced.

An especially preferred embodiment of this invention comprises a composition in which the R R R and R groups are substantially all hydrogen atoms, in which case the particular hydrazine-containing composition has the maximum specific impulse in proportion to its hydrazine content. The hydrocarbon groups which replace the hydrogen atoms on the hydrazine can have from one to about twelve carbon atoms. Since, however, the specific impulse decreases with increase in the number of carbon atoms in the hydrocarbon group,.it is preferable that the latter have from one to about 8 carbon atoms. The hydrocarbon groups can be alkyl, cycloalkyl, aryl, arylkyl, alkaryl, etc. Non-limiting examples of hydrazine compounds are: hydrazine, methyl hydrazine, dimethyl hydrazine, trimethyl hydrazine, tetramethyl hydrazine, ethyl hydrazine, diethyl hydrazine, N-methyl-N'-ethy1 hydrazine, propyl hydrazine, unsymmetrical dibutylhydrazine, phenyl hydrazine, diphenyl hydrazine, methyl phenyl hydrazine, etc.

When the carbon, hydrogen, and nitrogen-containing compounds employed in the composition of this invention are amines, they may be primary, secondary, or tertiary amines. The-hydrocarbon parts of the amino-substituted compound may be straight chain, branched chain, or cyclic. The hydrocarbon part may be saturated or unsaturated aliphatic, or aromatic. Non-limiting examples of nitrogen-containing hydrocarbons are: methylamine, dimethylamine, trimethylamine, ethylamine, diethylamine, propylamine, butylamine, amylamine, hexylamine, octylamine, laurylamine, ethylenediamine, trimethylenediamine, hexamethylenediamine, octamethylenediamine, dodecamethylenediamine, diethylenetriamine, triethylenediamine, hexaethyleneheptamine, dimethyltriethylenediamine, cyclohexylamine, allylamine, piperidine, aniline, N- methylaniline, N,N-diethylaniline, toluidine, phenylenediamine, anisidine, diphenylamine, etc. When the carbon, hydrogen, and nitrogen-containing compounds are heterocyclic nitrogen compounds, they include Z-aminopyridine and 3-amino quinoline, etc. Nitrate salts of the above amines, such as the nitrate salt of methylamine, can also be used. While componnds having from 1 to about 12 carbon atoms, and from 1 to about 7 nitrogen atoms are used in the preparation of the composition of this inventron, the preferred amines are those having from 1 to about 8 carbon atoms and from 1 to about 3 nitrogen atoms, as it is found that these compounds impart the highest degree of stability to the hydroxylamine compounds as well as to the hydrazine compound compositions with a minimum decrease in the specific impulse.

The hydroxy-substituted hydrocarbons and organic oxides which are employed in preparing the compositions of this invention include compounds such as alcohols, phenols, naphthols, alxylene oxides, and diphenylene oxide. The alcohols include aliphatic alcohols, both saturated and unsaturated, having either straight or branch chain hydrocarbon components in the compound. Nonlimiting examples of the alcohols include: methyl alcohol, ethyl alcohol, n-propyl alcohol, isopropyl alcohol, allyl alcohol, n-butyl alcohol, isobutyl alcohol, tert-butyl alcohol, cyclohexanol, octanol, lauryl alcohol, benzyl alcohol, cyclopentanol, glycol, diethyleneglycol, triethyleneglycol, hexaethyleneglycol, glycerol, 1,2,3,4,5,6-hexahydroxyhexane, etc. Non-limiting examples of hydroxysubstituted aromatic hydrocarbons include such compounds as: phenol, m-, and p-cresol, hydroxydiphenyl, cyclohexylphenol, thymol, guaniacol, eugenol, catechol, pyrogallol, hexahydroxybenzene, naphthol, etc. While hydroxy-substituted hydrocarbons having from 1 to about 12 carbon atoms and from 1 to about 6 hydroxy groups are employed in the composition, the preferred hydroxysubstituted hydrocarbons are those having from 1 to about 8 carbon atoms and from 1 to about 3 hydroxy groups, with from O to about 4 ether-type oxygen atoms in the compound, i.e., oxygen atoms which are connected by single bonds to two different carbon atoms which in turn are bonded to each other only through said oxygen atom. The compounds having 1 to about 8 carbon atoms, etc., are preferred since they impart the maximum amount of stability to the hydroxylamine-type compounds and hydrazine-type compounds with the minimum decrease in the overall specific impulse.

Non-limitin examples of hydrocarbon compounds having both hydroxy substituents and amino nitrogens therein include: ethanolamine, diethanolarnine, triethanolamine, l-hydroxy--amino-hexane, 1 hydroxy-lZ-amino dodecane, l-hydrox -8-amino octane, o-aminophenol, maminophenol, p-aminophenol, p,p di(hydroxyphenyl) amine, tri-2-(Z-hydroxyethoxy)ethylamine,

1,3,5-triaminoctanol, etc. As above, hydroxy and aminosubstituted hydrocarbons having from 2 to about 8 carbon atoms, 1 to aoout 3 hydroxy groups, from 1 to about 3 nitrogen atoms, and from O to about 3 ether-linked oxygen atoms are preferred.

The ketones which are employed as a component in the composition of this invention incmde such compounds as acetone, iethyl ethyl ketone, pentyl hexyl ketone, propylbutyl ketene, acetoacetone, urea, N-rnethyl urea, N,N- dime'thyl urea, N-ethyl urea, N,N-dibutyl urea, etc. Thus, the ketones have from 1 to about 12 carbon atoms, from 1 to about 3 oxygen atoms, and from 0 to about 2 amino nitrogens. Compounds having from 1 to about 8 carbon atoms, 1 oxygen atom, and from O to about 2 nitrogen atoms are preferred for the reasons given above.

The amount of additive compounds in the composition, other than hydroxylarnines and hydrazines, as stated hereinabove, is from 0 to about 75 wt. percent, based on the total weight of the composition. When these compounds are used in addition to the hydroxylamines or to hydroxylaminehydrazine compositions, stabilizing efiects with respect to thermal decomposition are noted when the amount of such compounds is as low as 0.1 wt. percent, based on the total weight of the composition. While this small amount of additives can be employed, it is preferred to use at least about 0.5 wt. percent in order to achieve a significant improvement in stability. It is especially preerred to use the additives in amounts of at least about 1 wt. percent for a more practical effect. An even more preferred embodiment of this invention is to employ the additive compounds in amounts of about wt. percent or more, based on the total weight of the composition in order to take a greater advantage of the stabilizing efiect of the additive compounds. Amounts of the stabilizing compound above about 75 Wt. percent, based on the total weight of the composition, can also be used; however, in order not to decrease the specific impulse of the composition, amounts of the stabilizing compound above about 75 wt. percent are not contemplated. Significant improvement in the stability of the hydroxylamine-type and hydrazine-type compound-containing composition, with a minimum of loss in the specific impulse characteristic of the composition, is achieved when the stabilizing compounds are employed in amounts of from about 1 to about 50 wt. percent, based on the total weight of the composition, and this, therefore, constitutes a preferred embodiment of this invention. For example, 0- methylhydroxylamine containing 10 wt. percent ethanol, based on the total weight of the hydroxylamine and ethanol, is less susceptible to thermal decomposition when the composition is employed in the operation of a rocket motor. When O-methylhydroxylamine is employed as a fuel without any stabilizing compound added, premature detonations are observed.

An especially preferred amount in which the additive compounds are added to the hydroxylamine-type compound containing composition is from about 5 to about 15 wt. percent, based on the total weight of the composition. It is found that amounts of the improving component within this range stabilize the hydroxylamine-type compound composition considerably against explosive decomposition over a wide variation of operating conditions.

All the chemical compounds which constitute components of the composition of this invention are well known and are commercially available. Processes for their preparation are described in standard chemical texts such as Organic Chemistry, by Fieser and Fieser, 1944 edition, published by D. C. Heath and Company, New York, as well as other published literature in the chemical field. The methylhydroxylamines were prepared by the process described by Bissort et al., Journal of American Chemical Society, 79, 796 (1957). A lengthy discourse on the preparation of the various compounds is, therefore, not included in this writing.

The rocket propellant compositions of this invention are prepared by mixing the various components together in the amounts required to obtain the desired composition and then subjecting the mixture to agitation as by stirring, shaking, etc., until a homogeneous composition is obtained. it is immaterial in what order the components are added to the container in which the mixing is effected. For example, the additive may be added to the hydroxylamine-type compound or conversely the hydroxylaminetype compound may be added to the additive or combination of two or more additives. Care must be exercised, however, since the hydroxylamines are susceptible to shock detonation.

The following examples are illustrative of the compositions of this invention and their performance.

EXAMPLE I To a container equipped with means for agitation are added 25 parts by weight of O-methylhydroxylamine and 75 parts by weight of ethanol. The mixture is subjected to agitation until a homogeneous composition is obtained. The composition is then detonation-tested in a reaction chamber consisting of a cylinder and piston arrangement. One end of the cylinder is closed with a flexible daiphragm which is subject to distortion or rupture depending on the force exerted within the confined space in the cylinder upon detonation of the composition confined therein. The piston is adapted to slide Within the cylinder so as to exert pressure on the confined components. The cylinder is equipped with gas inlet and outlet means for the purpose of controlling the atmosphere within the enclosure, and with means for heating the fuel composition. O'-methylhydroxylamine-ethanol fuel composition in the amount of 0.5 cc. is placed on the bottom of the cylinder. The top of the cylinder is closed by partially inserting the piston. An atmosphere of nitrogen is provided through the gas inlet means. The fuel composition in the cylinder is then subjected to adiabatic compression by a rapid downward stroke of the piston. The explosion or detonation of the fuel subjected to compression is indicated by the condition of the diaphragm at the bottom of the cylinder. When the composition of this example is subjected to adiabatic compression no detonation is observed.

EXAMPLE H O-methylhydroxylamine was detonation-tested in the apparatus described in Example 1 Without the presence of additives. The hydroxylamine detonated, rupturing the diaphragm at the bottom of the cylinder.

EXAMPLE HI O-methylhydroxylamine, containing 10 wt. percent methanol, based on the total Weight of the composition, was tested in the detonation test equipment described in Example I. The diaphragm did not break, indicating a stabilization of the composition.

In like manner, a composition consisting of 50 wt. percent O-methylhydroxy-lamine and 50 Wt. percent methanol is found to be stabilized against shock detonation.

EXAMPLE IV A composition consisting of O-methylhydroxylamine, together with 10 wt. percent hydrazine, H NNH based on the total weight of the composition, was tested in the detonation equipment. The diaphragm was not ruptured.

In like manner, a composition consisting of 1 wt. percent O-methylhydroxylamine and 99 wt. percent hydrazine does not detonate upon adiabatic compression. A composition consisting of wt. percent hydrazine and 95 wt. percent O-methylhydroxylamine is also stabilized against shock detonation. Likewise, a composition consisting of 50 Wt. percent O-methylhydroxylamine and 50 wt. percent hydrazine is stabilized against shock detonation.

EXAMPLE V A composition consisting of 90 wt. percent O-methylhydroxylamine and Wt. percent unsymmetrical diamethyl hydrazine was found to be stabilized against shock detonation when tested in the apparatus described in xample I. The diaphragm did not rupture.

A composition consisting of 0.1 Wt. percent didodecyl hydrazine and 99.9 wt. percent O-methylhydroxylamine is also stabilized against shock detonation. In like manner, a composition consisting of 99.5 wt. percent O-methylhydroxylamine and 0.5 -wt. percent dioctyl hydrazine is stabilized against shock detonation. A composition consisting of 99 Wt. percent O-methylhydroxylamine and 1 wt. percent hydrazine is likewise stabilized against shock detonation. A composition consisting of 0.1 wt. percent O-rnethylhydroxylamine and 99.9 wt. percent monomethyl hydrazine is found to be stable against shock detonation. Likewise, a composition consisting of 0.5 wt. percent 0- methylhydroxylamine and 99.5 wt. percent mono'ethylhydrazine is found to be stable against shock detonation. Another composition which is likewise stabilized is one consisting of 1 wt. percent O-methyldroxylamine and 99 wt. percent hydrazine.

EXAMPLE vi A composition consisting of 90 Wt. percent O-methyh hydroxylamine and 10 Wt. percent ethylenediamine was found to be stabilized against shock detonation When tested in the equipment described in Example 1.

EXAMPLE vn A composition consisting of 0.1 wt. percent N-mcthylhydroxylamine and 99.9 Wt. percent hydrazine, based on the weight of the hydroxylamine and hydrazine present, together with 0.1 wt. percent dodecyl alcohol, based on the total weight of the composition, is found to be stabilized with respect to its detonation characteristics.

In like manner, a composition consisting of 0.5 wt. percent N-ethylhydroxylamine and 99.5 wt. percent hydrazine, based on the Weight of the ethyihydroxylarnine and hydrazine present, together with 0.5 wt. percent ethyl alcohol, based on the total weight of the composition, is stabilized against decomposition at high temperatures. A composition of 1 wt. percent O-dodecylhydroxylamine and 99 Wt. percent hydrazine, based on the Weight of the hydroxylamine and hydrazine present, together with 1 Wt. percent ethyl alcohol, based on the total Weight of the composition, is stabilized against decomposition. Another composition that is stabilized against high temperature decomposition is one consisting of 0.5 wt. percent tridodecylhydroxylamine and 99.5 Wt. per cent monomethy-l hydrazine, based on the weight of the hydroxylamine and hydrazine present, together with Wt. percent methyl alcohol, based on the total Weight of the composition. Likewise, a composition consisting of 1 wt. percent tripopylhydroxylamine and 99 wt. percent monomethyl hydrazine, based on the weight of the hydroxylamine and hydrazine present, together with 5 Wt. percent cyclopentanot, based on the total weight of the composition, is found to be stabilized against high temperature decomposition. A composition consisting of 50 Wt. percent u,fi-diethyll1ydroxylamine and 50' Wt. percent hydrazine, based on the weight of the hydroxylamine and hydrazine present, together with Wt. percent ethyl alcohol, based on the total weight of the composition, is stabilized against high temperature decomposition.

The following table illustrates still other compositions WHlCh are prepared according to this invention.

Table I Compounds Added to Weight N o. O-methylh ydroxylaminc Percent Additive Methylamine. 0. 1 Dodccylamine l5 Octylamine 5 Oyclohexylam 2 Ethylamine 75 Ethylencdiaminc 50 Hexaethylenehcptalninc 1g 0. 5 10 1 20 10 10 10 25 1 2 0. 5 0. 1 0. 5 1

V 2 Hexahydroxybcnzene. 0. 1 Diethyleneglycol 5 Pcntacthylenoglycol- 5 Hexacthylene glycol 10 Alpha-Naphthol 10 Hydroquinane. 10 Ethanolaminm. 75 Diethanolamine 50 l-hydroxy-12aminododecane 20 Triethanol amine 0. 5 B-hydroxycthylhydraziue 20 1-11 ydroxy-8-amino octane 1 fi-hydroxypyridine 15 Tri-Z-(Q-hydroxycthoxy)ethylamine. 2 p-AminophenoL O. 1 a-naphtholamine 5 Acetone 75 Methyl ethyl keto 50 Propyl butyl ketone 0. 5 2,4Pcntanedionc. 1 Allylphenone 25 2,4,6-Oetanetrione. 10 Urea 10 N-methylurca 25 N-dodeeylurea O. 1 N ,N-dimethylurca 75 N-ethylurca 1 0.5 20 5 15 5 Ethauolaminc 5 Table IContinued Compounds Added to Percent Additive Ethanolamine Monomethyihy {C yclopentanol Unsymmetric a1 dimethyl-hydrazine1 Hydrazine {Hydrazine 1 Oetylarnine f M onomethylhydrszine 1 lAniline {Unsymmetrical dimethyl-liydrazme 1 [Pyridine [Hydrazine JHydrazine lDiethyl enetriamine Ethylenediaminc 1 {Hydrazine 11 W thylamme 1 {Hydrazine .Ethanolamine 1 {Monopropylhydrazine l-hydroxy-S-amino octane 1 {Unsymmettical dimethyl-hydrazine1 u-naphtholamine" Hydrazine 11111 11 lTriethanolamine Hydrazine 1 B enzylamine1 [Hydrazine 1 1 1 lp-A minophenol 1 Hydrazine 1 1 Ethanolaznine {Hydrazinm 11 A 0.

{Methyl ethyl ketone Unsynmietrieal dimethyl-hydrazlno \Urea. 1 73 fllydrazine.

{H drazine 111111111111 1. N, N-dimethyl urea li ydrazine UIOl 1. 1.

Hoomzo in the table set out above, and throughout this writing, except as otherwise indicated, the weight percent of addi- "ve is based on the total weight of the composition.

The performance of the compositions of this invention as rocxet propellants was investigated by operating stationary rocket motors using the improved hydroxylamine compositions of this invention as the propellant fuel together with a suitable oxidizer. The rocket engine employed in the tests had a throat area of 67.2 sq. in. The ratio of the cross-sectional area of the nozzle exit-to-tln'oat cross-sectional area was 25:-l. The ratio of the crosssectional area of the combustion chamber to the crosssectional area of the throat was 1.8:1. The motor was operated at a combustion chamber pressure of 756 p.s.i.a. and an exit nozzle pressure of substantially 13.6 p.s.i.a. The fuel composition and oxidizer were fed through separate conduits from individual storage containers to the combustion chamber Where the stream of the fuel composition and the stream of oxidizer contacted each other. The fuel and oxidizer ignited on contact, producing gaseous products as a result of the spontaneous combustion of the components of the two streams. The gaseous products were eiected from the combustion chamber through the throat area and then out into the atmosphere through the exit nozzle. The ejection of the reaction product gases from the combustion chamber produces a thrust which is measured by means of a load cell mounted forward of the motor. The fuel composition and the oxidizer were metered into the motor so that the amount reacting within any particular period of time was known.

EXAMPLE VIII The rocket motor described hereinabove was operated on a fuel consisting of hydroxylamine. The oxidizer used was nitrogen tetroxide, N 0 The specific impulse, 1 obtained with this fuel was 285 seconds.

EXAMlLE TX The procedure of Example VIII is repeated, using the fuel composition of Example H, with nitrogen tetroxide as oxidizer. Good performance is obtained.

EXAMPLE X The motor described above was operated on hydrazine fuel with no additive. The motor disintegrated explosively after ignition of fuel and oxidizer in the combustion chamber.

When the procedure of Example VIII is repeated using the fuel composition of Example Ill with hydrogen peroxide as the oxidizer and an oxidizer-to-fuel weight ratio equivalent to 0.5 of the stoichiometric value, satisfactory operation of the motor is observed. Good results are also obtained when a fuel composition of Example 1V is employed, using chlorine tritluoride as the oxidizer, with an oxidizer-to-fuel weight ratio equivalent to 0.8 of the stoichiometric value. Likewise, good results are obtained when the composition of Example V is employed as the fuel and bromine pentafiuoride as the oxidizer, with an oxidizer-to-fuel ratio equivalent to unity in terms of the stoichiometric value. improved operation of the rocket motor is also observed when the fuel of Example V1 is employed with liquid oxygen as the oxidizer, with an oxidizer-to-fuel weight ratio equivalent to 1.2 of the stoichiometric value of the ratio. In like manner, improved operation of the rocket motor is observed when the fuel of Example VII is employed with white fuming nitric acid as the oxidizer, and an oxidizer-to-fuel weight ratio equivalent to two times the stoichiometric value of the ratio. In like manner, the operation of the motor is improved when fuel N0. 62 of the above table is employed and red fuming nitric acid is used as the oxidizer, with an oxidizer-to-fuel weight ratio of 1.5 times the stoichiometric Walue of the ratio. Improved performance in the rocket motor is also obtained when the motor is operated on the other compositions shown in the table hereinabove, with oxidizers which include liquid fluorine, liquid fluorine and liquid oxygen mixtures of from about 5 to about mol. percent fluorine in oxygen, nitrogen tetroxide, perchloryl fluoride having the general formula FClO and nitrogen trifluoride.

The ratio of oxidizer-to-f-uel is calculated on a weight basis. The values given above are in terms of multiples of the stoichiometric value of the ratio. The stoichiometric value of the ratio can be further defined as that value of the ratio when the oxidizer and fuel are used in stoichiometric proportions. The oxidizer-to-fuel weight ratio can vary from about 0.5 of the stoichiometric ratio value to about two times the stoichiornetric ratio value. For better rocket performance With respect to thrust and range, however, oxidizer-to-fuel weight ratios equivalent to from about 0.8 to about 1 of the stoichiometric ratio value are preferred.

When a flight rocket is operated employing the composition of Example I, satisfactory flight performance, with no detrimental explosions, is observed. Similarly, good results are obtained when a flight rocket is operated on the other fuels disclosed in this invention.

From the discussion and examples given hereinabove, it is seen that a novel rocket propellant fuel is provided having enhanced stability and a high specific impulse upon use in a rocket motor. A word of caution with respect to the use of these compositions as rocket propellants may be in order at this point. Rocket fuels in general are highly explosive, and explosions may occur even when it is believed that all safety precautions have been observed. It is, therefore, advisable to treat all rocket fuel compositions as highly explosive and dangerous materials for handling purposes. For example, inethylhydroxylamine fuel with added ethanolamine in the amount of 10 weight 11 percent, when properly mixed so as to produce a homogeneous composition, enhances the stability of the fuel. If, however, the ethanolamine is not thoroughly mixed with the hydroxylamine, explosion of the fuel may readi- 1y occur.

While the composition and method of this invention have been described in some detail with the use of specific illustrative examples, it is not intended that the spirit or scope of this invention in limited except as indicated in the appended claims.

I claim:

1. A method of producing thrust which comprises ejecting from a reaction chamber the gaseous products produced by the spontaneous combustion of an oxidizer and a liquid fuel composition consisting essentially of hydroxylamines having the general formula wherein R R and R are selected from the class consisting of hydrogen and hydrocarbon groups havingfrom 1 to about 12 carbon atoms.

2. The method of claim 1, wherein thehydroxylamine is methyl hydroxylamine.

3. A composition of matter consisting essentially of a hydroxylamine having the general formula NOR3 wherein R R and R are selected from the class consisting of hydrogen and hydrocarbon groups having from 1 to about 12 carbon atoms and at least about 0. 1 percent, based on the total weight of the composition, of a hydrazine compound having the general formula wherein each of R R5, R and R is individually selected from the class consisting of hydrogen and hydrocarbon groups having from 1 to about 12 carbon atoms and wherein at least 75 percent of the sum of said R R R and R groups in the composition as a whole are hydrogen atoms.

4. A composition of matter consisting essentially of an hydrazine having the general formula wherein each of R R R and R is individually selected from the class consisting of hydrogen and hydrocarbon groups having from 1 to about 12 carbon atoms, and wherein at least about 75 percent of the sum of R R R and R groups in the composition as a whole are hydrogen atoms, and at least about 0.1 percent, based on the total weight of the composition, of a hydroxylamine having the general formula wherein R R and R are selected from the class consisting of hydrogen and hydrocarbon groups having from 1 to about 12 carbon atoms.

5. A composition of matter consisting essentially of from 1 to 99 percent, based on the total weight of the composition, of a hydroxylamine having the general formula wherein R R and R are selected from the class consisting of hydrogen and hydrocarbon groups having from 1 to about 12 carbon atoms, and from 1 to 99 percent of a hydrazine compound havingthe general formula wherein each of R R R and R is individually selected from the class consisting of hydrogen and hydrocarbon groups having from 1 to about 12 carbon atoms and wherein at least 75 percent of the sum of said R R R and R groups in the composition as a whole are hydrogen atoms.

6. The composition of claim 3 and at least 0.1 percent, based on the total weight of the composition, of a compound containing only carbon, hydrogen and nitrogen, said compound selected from the class consisting of amines and nitrate salts of amines, said compound having from 1 to about 12 carbon atoms and from 1 to about 7 nitrogen atoms, said composition being further characterized in that the total amount of hydrazine compound combined with the total amount of hydroxylamine compound is at least about 25 percent, based on the total weight of said composition.

7. The composition of claim 3, and at least about 0.1 percent of an alcohol containing only carbon, hydrogen, and oxygen and having from 1 to about 12 carbon atoms, from 1 to about 6 hy'droxygroups and from 0 to about 5 ether-linked oxygen atoms, said composition being further characterized in that the total amount of hydrazine compound combined with the total amount of hydroxyl amine compound is at least about 25 percent, based on the total weight of said composition.

8. The composition of claim 3, and at least 0.1 percent of a hydroxy-substituted hydrocarbon amine having from 2 to about 12 carbon atoms, from 1 to about 3 nitrogen atoms, from 1 to about 3 hydroxy groups, and from 0 to about 3 ether-linked oxygen atoms, said composition being further characterized in that the total amount of hydrazine compound combined with the total amount of hydroxylamine compound is at least about 25 percent, based on the total Weight of said composition.

9. The composition of claim 3, and at least 0 .1 percent of a compound selected from the class consisting of ketones having from 3 to about 12 carbon atoms, from 1 to 2 (J O groups, and ureas having from O to about 2 hydrocarbon substituents on the nitrogens thereof, wherein said substituents have from 1 to about 4 carbon atoms, said composition being further characterized in that the total amount of hydrazine compound combined with the total amount of hydroxylamine compound is at least about 25 percent, based on the total weight of said composition.

1 0'. A composition of matter consisting essentially of a hydroxylamine having the general formula -OR3 Rf wherein R R and R are selected from the class consisting of hydrogen and hydrocarbon groups having from 1 to about 12 carbon atoms, and at least about 0.1 percent, based on the total weight of the composition, of a compound containing only carbon, hydrogen, nitrogen, and oxygen selected from the class consisting of amines and nitrate salts of amines, said compounds having from 1 to about 12 carbon atoms and from 1 to about 7 nitrogen atoms.

11. A composition of matter consisting essentially of a hydroxylamine having the general formula wherein R R and R are selected from the class consisting of hydrogen and hydrocarbon groups having from 1 to about 12 carbon atoms, and at least about 0.1 percent, based on the total weight of the composition, of a hydroxysubstituted hydrocarbon amine having from 2 to about 12 carbon atoms, from 1 to about 3 nitrogen atoms, from 1 to about 3 hydroxy groups, and from O to about 2 hydrocarbon substituents on the nitrogens thereof wherein said substitueuts have from 1 to about a carbon atoms.

12. A composition of matter consisting essentially of a hydroxylamine having the general formula N-ORs R2 wherein R R and R are selected from the class consisting of hydrogen and hydrocarbon groups having from 1 to about 12 carbon atoms, and at least about 0.1 percent, based on the total weight of the composition, of a urea having from to about 2 hydrocarbon substituents on the nitrogens thereof, wherein said substituents have from 1 to about 4 carbon atoms.

13. The composition of claim 5, wherein at least about 75 mole percent of said hy'droxylamine is a mon-methyl substituted hydroxylamine.

14. The composition of claim 13, wherein said monomethyl substituted hydroxylamine is O-methyl hydroxylamine.

15. The composition of claim 7, wherein said alcohol is ethanol and said hydroxylamine is a methyl-substituted hydroxylamine.

16. The composition of claim 5, wherein said hydrazine compound is hydrazine and said hydroxylamine is 0- methyl hydroxylamine.

17. The composition of claim 10, wherein said hydroxylamine is O-methyl hydroxylamine and said amine is ethylenediamine.

18. A method of producing thrust which comprises ejecting from a reaction chamber the gaseous products produced by the spontaneous combustion of an oxidizer and the composition of claim 5.

19. A method of producing thrust which comprises ejecting from a reaction chamber the gaseous products produced by the spontaneous combustion of an oxidizer and the composition of claim 6.

20. A method of producing thrust which comprises ejecting from a reaction chamber the gaseous products produced by the spontaneous combustion of an oxidizer and the composition of claim 7.

21. A method of producing thrust which comprises ejecting from a reaction chamber the gaseous products produced by the spontaneous combustion of an oxidizer and the composition of claim 8.

22. A method of producing thrust which comprises ejecting from a reaction chamber the gaseous products produced by the spontaneous combustion of an oxidizer and the composition of claim 9.

23. A method of producing thrust which comprises ejecting from a reaction chamber the gaseous products produced by the spontaneous combustion of an oxidizer and the composition of claim 10.

24. A method of producing thrust which comprises ejecting from a reaction chamber the gaseous products produced by the spontaneous combustion of an oxidizer and the composition of claim 11.

25. A method of producing thrust which comprises ejecting from a reaction chamber the gaseous products produced by the spontaneous combustion of an oxidizer and a liquid fuel composition consisting essentially of a hydroxylamine having the general formula wherein R R and R are selected from the class con sisting of hydrogen and hydrocarbon groups having from 1 to about 12 carbon atoms and at least 0.1 percent, based on the total amount of said liquid fuel composition, of an :alcohol containing only carbon, hydrogen, and oxygen, and having from 1 to about 12 carbon atoms, from 1 to about 6 hydroxy groups, and from 0 to about 5 ether-linked oxygen atoms.

26. A method of producing thrust which comprises ejecting from a reaction chamber the gaseous products produced by the spontaneous combustion of an oxidizer and a liquid fuel composition consisting essentially of a hydroxylamine having the general formula wherein R R and R are selected from the class consisting of hydrogen and hydrocarbon groups having from 1 to about 12 carbon atoms and at least 0.1 percent, based on the total amount of said liquid fuel composition, of a compound selected from the class consisting of ketones having from 3 to about 12 carbon atoms, from 1 to 2 C=0 groups, and ureas having from 0 to about 2 hydrocarbon substituents on the nitrogens thereof, wherein said substituents have from 1 to about 4 carbon atoms.

References Cited in the file of this patent UNITED STATES PATENTS 2,636,342 Cade Apr. 28, 1953 2,693,077 Malina et al. Nov. 2, 1954 OTHER REFERENCES Jones et al.: I.A.C.S. (1928), pp. 2742-7. 

1. A METHOD OF PRODUCING THRUST WHICH COMPRISES EJECTING FROM A REACTION CHAMBER THE GASEOUS PRODUCTS PRODUCED BY THE SPONTANEOUS COMBUSTION OF AN OXIDIZER AND A LIQUID FUEL COMPOSITION CONSISTING ESSENTIALLY OF HYDROXYLAMINES HAVING THE GENERAL FORMULA 